Re: [ietf-smtp] DSNs

Alessandro Vesely <vesely@tana.it> Tue, 21 April 2020 09:00 UTC

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From: Alessandro Vesely <vesely@tana.it>
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Subject: Re: [ietf-smtp] DSNs
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On 18/04/2020 21:41, Viktor Dukhovni wrote:
> And likewise Postfix also implements RFC3461.  It is on by default.


Ditto for Courier-MTA.


> I turn it off on inbound edge systems, and ignore remote "DSN" on
> outbound edge systems.  That way, any DSNs are sent within either my
> or the remote ADMD, but not across ADMD boundaries.


May I ask why?  I may be dumb, but I don't see the risk of letting positive
DSNs be returned when (rarely) requested.  Yes, it may betray forwarding, but
so do negative DSNs, e.g. in case of mailbox full.  Is that the concern?


Best
Ale
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